| Python基本數據類型(元組) |
一、概述
元組(Tuple)是一種與列表類似的序列類型。元組的基本用法與列表十分類似。只不過元組一旦創建，就不能改變，因此，元組可以看成是一種不可變的列表。
二、元組格式
Python用一對括號“（）”生成元組，中間的元素用逗號“，”隔開。盡量在最后元素后面加上一個額外的逗號“，”加以區分括號與元組，特別是只含單元素的元組：
tu = (11,22,"alex",[(33,44)],)
三、元組與列表的相互轉換
列表和元組可以使用tuple()函數和list()函數相互轉換：
li = [3,6,1,5,4,6] print(tuple(li)) #結果為：(3, 6, 1, 5, 4, 6) tu = (11,22,"alex",[(33,44)],) print(list(tu)) #結果為：[11, 22, 'alex', [(33, 44)]]
四、索引和切片
對於元組來說，只能通過索引和切片來取值，不能進行修改操作。
tu = (11,22,"alex",[(33,44)],) print(tu[3][0][1]) #結果為：44 print(tu[1:-1]) #結果為：(22, 'alex')
五、元組的方法
由於元組是不可變的，所有它只支持.count()方法和.index()方法，用法與列表一致：
.count()方法是計算元組的指定元素出現的次數。
tu = (11,22,"alex",[(33,44)],22,) print(tu.count(22)) #結果為：2
.index()方法是獲取指定元素第一次出現的索引位置。
tu = (11,22,"alex",[(33,44)],22,) print(tu.index(22)) #結果為：1
元組所有方法歸納：
1 lass tuple(object): 2 """ 3 tuple() -> empty tuple 4 tuple(iterable) -> tuple initialized from iterable's items 5 6 If the argument is a tuple, the return value is the same object. 7 """ 8 def count(self, value): # real signature unknown; restored from __doc__ 9 """ T.count(value) -> integer -- return number of occurrences of value """ 10 return 0 11 12 def index(self, value, start=None, stop=None): # real signature unknown; restored from __doc__ 13 """ 14 T.index(value, [start, [stop]]) -> integer -- return first index of value. 15 Raises ValueError if the value is not present. 16 """ 17 return 0 18 19 def __add__(self, y): # real signature unknown; restored from __doc__ 20 """ x.__add__(y) <==> x+y """ 21 pass 22 23 def __contains__(self, y): # real signature unknown; restored from __doc__ 24 """ x.__contains__(y) <==> y in x """ 25 pass 26 27 def __eq__(self, y): # real signature unknown; restored from __doc__ 28 """ x.__eq__(y) <==> x==y """ 29 pass 30 31 def __getattribute__(self, name): # real signature unknown; restored from __doc__ 32 """ x.__getattribute__('name') <==> x.name """ 33 pass 34 35 def __getitem__(self, y): # real signature unknown; restored from __doc__ 36 """ x.__getitem__(y) <==> x[y] """ 37 pass 38 39 def __getnewargs__(self, *args, **kwargs): # real signature unknown 40 pass 41 42 def __getslice__(self, i, j): # real signature unknown; restored from __doc__ 43 """ 44 x.__getslice__(i, j) <==> x[i:j] 45 46 Use of negative indices is not supported. 47 """ 48 pass 49 50 def __ge__(self, y): # real signature unknown; restored from __doc__ 51 """ x.__ge__(y) <==> x>=y """ 52 pass 53 54 def __gt__(self, y): # real signature unknown; restored from __doc__ 55 """ x.__gt__(y) <==> x>y """ 56 pass 57 58 def __hash__(self): # real signature unknown; restored from __doc__ 59 """ x.__hash__() <==> hash(x) """ 60 pass 61 62 def __init__(self, seq=()): # known special case of tuple.__init__ 63 """ 64 tuple() -> empty tuple 65 tuple(iterable) -> tuple initialized from iterable's items 66 67 If the argument is a tuple, the return value is the same object. 68 # (copied from class doc) 69 """ 70 pass 71 72 def __iter__(self): # real signature unknown; restored from __doc__ 73 """ x.__iter__() <==> iter(x) """ 74 pass 75 76 def __len__(self): # real signature unknown; restored from __doc__ 77 """ x.__len__() <==> len(x) """ 78 pass 79 80 def __le__(self, y): # real signature unknown; restored from __doc__ 81 """ x.__le__(y) <==> x<=y """ 82 pass 83 84 def __lt__(self, y): # real signature unknown; restored from __doc__ 85 """ x.__lt__(y) <==> x<y """ 86 pass 87 88 def __mul__(self, n): # real signature unknown; restored from __doc__ 89 """ x.__mul__(n) <==> x*n """ 90 pass 91 92 @staticmethod # known case of __new__ 93 def __new__(S, *more): # real signature unknown; restored from __doc__ 94 """ T.__new__(S, ...) -> a new object with type S, a subtype of T """ 95 pass 96 97 def __ne__(self, y): # real signature unknown; restored from __doc__ 98 """ x.__ne__(y) <==> x!=y """ 99 pass 100 101 def __repr__(self): # real signature unknown; restored from __doc__ 102 """ x.__repr__() <==> repr(x) """ 103 pass 104 105 def __rmul__(self, n): # real signature unknown; restored from __doc__ 106 """ x.__rmul__(n) <==> n*x """ 107 pass 108 109 def __sizeof__(self): # real signature unknown; restored from __doc__ 110 """ T.__sizeof__() -- size of T in memory, in bytes """ 111 pass 112 113 tuple